Where can I see who is logged into my Moodle course when I am in my course?
With editing turned on, at the bottom left corner of the course main page, there is an “Add a block” drop down menu. Choose “Online Users” to add the “Online Users” block at your course page.
The “Online Users” block shows the users who have been logged into the current site for a period of time set by the site administrator (default is 5 minutes). By clicking on the envelope icon next the student name, you are able to send an instant message to the student.